1. Field of the Invention
The present invention relates to a pulse wave detecting apparatus for detecting pulse wave produced by an arterial vessel of a living body.
2. Related Art Statement
The Applicant and others filed Japanese Patent Application No. 62-130879 in which they disclosed a pulse wave detecting apparatus having a semiconductor element which is pressed against a body surface of a subject such that the element is aligned with an arterial vessel of the subject, for detecting pulsation of the arterial vessel and converting the detected pulsation into electrical signal representing pulse wave corresponding to the pulsation. The above-indicated Japanese Patent Application was laid open under Publication No. 63-293424 on Nov. 30, 1988, which date is subsequent to the priority date Jan. 28, 1988 for the present application.
The properties of the above semiconductor element, however, usually change as time elapses. The semiconductor element whose properties have changed considerably largely after use over a long period of time, is inappropriate to further use for the pulse wave detecting apparatus, because pulse wave cannot be detected with sufficient accuracy through such semiconductor element.